I had Koni's on my 172 turbo, and i have to say the difference in the cars handling when adjusted was very noticeable!
Ive had 2 182's now with cup pack suspension. I put some Apex lowering springs on the 1st one and it firmed up the ride and decreased body roll to the point it felt just like the Koni's on Eibach Sportlines with the shocks on as stiff as they can go. With the Konis on full soft it felt just like driving a Cup Packed 182 with OEM Shocks and springs.
My honest opinion, unless youre doing 10-15 track days a year and are trying to be really quick id say the cost doesnt justify the expense of a set of new Koni's. For me it would be a case of keep your new cup shocks, get some stiffer springs (cooksports seem to be the craze at the moment) and you will get 95% of the Koni's performance/benefit at a fraction of the cost.
All IMHO of course